11 January 2009

The Extinction Theory of Scientific Progress

I bring this topic up as a recent History Channel program, First Apocalypse (link rot may set in as the History Channel doesn't do permalinks), featuring many fine folks, had many of those same folks asking inane and rhetorical questions that actually have answers via analysis. And by trying to be 'fair' the producers of the program did NOT perform their duties to then PRESENT how other geologists explain these happenings. That is part of their Armageddon Week thing, but, really, by only presenting the most hysterical, worse case imaginable scenarios, they are trying to drive a political agenda home on such lovely things like 'global warming'. That is neither history nor science in what was presented, and did a disservice to the general population not only on science but on the scientific method.

When going through my geology courses which were post Alvarez & Alvarez, there was a dichotomy in the scientific community that demonstrated a deep and abiding part of human culture. Almost invariably, in the mid-1980's, you could readily determine who was against the boloid extinction theory of the late Cretaceous: they had been geologists for more than 20 years. It was a steep and harsh dividing line that led to a primary observation in Geology, but is more widely applicable to all of the sciences, and I will paraphrase it from memory:

For geology theory to advance the preceding suite of scientists must go extinct.

The reason that the elder Alvarez was able to cut through the staid geological community was the he was a physicist, much respected in his field, and with his son who was a geologist did impeccable work on the K/T boundary layer marking the end of the Cretaceous and beginning of the Tertiary. By actually just looking, in detail, at what was contained in that global boundary layers, those two did groundbreaking work that ANYONE in geology could have done before that.

With that paleontology then asked a vital question: what was the set of characteristics that allowed those that survived to extinction event to do so?

There was one ready 'rule of thumb' on the extinction event: any land animal over 15kg of adult body mass didn't make it.

In the area of foraminifera, little one celled sea dwelling microbes responsible for all that lovely chalk due to their hard shells, this previous life form that had a huge number of species saw only ONE survive. It was telling as that was a polar dwelling foram that could spend large amounts of time out of sunlight, shut down its cell and sink deeper into the water column. All modern foraminifera come from that single, surviving, species.

Taken together along with only 50% of the forests surviving the extinction event, and many of those being less diverse, we now start to piece together the survivor's pictures.

From that we can answer some of the more inane questions presented throughout the program.

1) Frogs? How did they survive the fires, cold, and acid rain?

The Answer is: lifestyle. Frogs are semi-aquatic amphibians, and as sea life had a different survival sieve applied to it, the actual conditions of water must be examined for life forms. Water, in large bodies, has a slow uptake and release of heat energy. While the ground freezes rapidly in the northern climates, lakes, streams and other bodies of open water can go weeks before freezing over and only the most shallow freeze down to their bottom surfaces. Frogs lay their eggs in water, particularly lakes and streams. Frogs survive this thing known as 'winter' via their eggs, when they don't seek underground shelter, which some do, to this day. Indeed, in desert climates with NO open bodies of water, after a major rainstorm you will find frogs and toads breeding happily and then heading into a muddy underground to wait out surface conditions. As for acid rain, New York State and Quebec have many lakes with high pH values and they, still, have frogs.

Plus 50% of the forests made it through... add in just a few lakes and streams and you get survival.

The question, itself, is inane, trying to paint frogs and toads as 'weak' while, in fact, they have a diverse method of surviving some of the harshest climates on the planet, often as opportunist breeders, and continuing in places where we normally don't picture them. Their very position being amphibians and small, with diverse survival techniques, actually brings up the question of 'how do you kill off all frog and toad species in a single extinction event?' a relevant one.

2) Like frogs, insects were brought up in the program.

Again the answer is lifestyle. Insects do this thing known as 'laying eggs' often underground to avoid swings in surface conditions. While many did roast in the large scale forest fires, probably to ash, their eggs would not do so. Our own knowledge of places like Yellowstone and its fires points to this. Also, 50% of forests were not destroyed by larger destruction, offering safe havens for those that could survive in those areas. And the only thing that breeds faster than rabbits are cockroaches and flies.

3) Sea life. Why did some species survive and others didn't during the following wide swings in temperatures?

Take a look at the semi-aquatic to aquatic survivors and you piece together an answer. Starting with the crocodilians, going on to sea turtles and then on to sharks and such, we see a group that falls into two major areas. First are those with a relatively slow metabolism that don't need to eat much. The larger land crocks didn't make, but their smaller brethren did. Ditto the sea turtles. These animals do not have high metabolisms, can exist off of scanty meals and exist in this medium known as 'salt water' which is harder to freeze than fresh water. They have a scavenger mode to gain food and are general opportunist hunters and eaters. State of decay doesn't matter much to them, just eat it and let the slow metabolism take care of it. That goes for herbivores, too, especially ones not locked in to a single type of plant source. And I've seen turtles happily munch on meat from various sources, so the idea that they are in any way more 'vulnerable' while having a wide appetite, slow metabolism and long life makes them a non-question: they had the tools to survive that others didn't have.

When you say 'opportunistic feeder' have you ever tried to capture just what something like a Tiger Shark goes after? In the stomachs of them have been found: tin cans, boots, hub caps, socks, and often things like human limbs. If nothing else we have learned that the main way for a shark to check to see if something is in the 'food' category, is to apply its most sensitive area to it. That is, unfortunately, its mouth. Great White sharks survived the K/T boundary as they were *already* living in the Cretaceous polar seas and had a wide ranging lifestyle. Plus, once you go down fifty or a hundred feet, you find sea life that exists on the dead remains filtering down to them from above, and they probably went through that just fine.

Ammonites, however, seem to have many of the adaptations of their squid brethren who got rid of shells, and continued happily right up to the boundary layer. One of their cousins did survive: the Nautilus. That survivor is one that readily adapts to different depths as part of its diurnal cycle and is just as happy to feed at fifty or one hundred feet down as it is at ten feet. Other ammonites could do so, but we have no idea why they didn't make it and their close cousin did. Thems the breaks in extinction events.

4) Where are the bodies of the dinosaurs at the K/T boundary?

That is asked in a serious tone!

The counter question is given the length of time dinosauria (and the entire suite of fauna and flora of that period) were around (approx. 80 million years) then where are all these animals and plants?

The conditions proposed in those areas hardest hit by the asteroid impact posit wide-ranging forest and open-land destruction with high temps over a period of weeks, not days. In those areas I wouldn't expect there to be much of *any* evidence of dinosaurs, plants, or anything that would succumb to high heat for a prolonged period of time. In geographically isolated areas of forest or other ecological areas of survival, their very insularity points to small populations for larger animals. Indeed when elephants, Mammoths and Mastodons got everywhere, your ability to find them meant getting to ready food sources or the travel areas between them. Large herbivores have a negative survival capacity in geographically isolated areas as they need more food than the surroundings can provide, particularly if there are wide climate swings. Those predators adapted to going after them face a similar problem, but predators are far scarcer on the ground to start with. Look at modern felonid populations in the wilds of Africa and Asia and you get one animal per every X number of square miles with the smallest I've seen for X being 10 and the largest being 50 or so. Look at wolves and you get similar results that vary per body mass.

To tell you how disingenuous the question is, let me take up the exact, same idea presented by true frauds and those unwilling to face historical facts. I don't like it, but this is the question these folks ask:

'Where are the dead bodies of all the Jews from the Holocaust?'

Yeah, its almost the exact, same question, just put in dinosaurs for Jews and K/T extinction event for Holocaust. As if high heat doesn't happen to do something to skeletons, you know?

As Sec. Def. Rumsfeld quipped: absence of evidence is not evidence of absence. The flora biota that can be retrieved from spores and such indicate a continuous biota right up to the K/T boundary on a global scale. That is the environment of dinosaurs. Also, that continuous environment automatically kills other extinction event theories, like the Deccan Traps flood basalts being so horrific that it changed global climate, save for all the plants that merrily continued on throughout that period. Strange, that.

Like all fossil finds, we have the general rule that preservation is rare, often unique due to climate and circumstances. Pointing at feet of layers of rock without telling the time-span covered does not tell you about deposition rate nor environment, so the fellow sitting and overlooking a canyon is only pointing to a few million years of deposition for a final few feet of rock. What was the climate for that deposition? Well the rock looks pretty continuous until the K/T... the chances of finding a fossil dinosaur depends on where it died, when it died, what the predation conditions were and what the deposition conditions were. Almost all of the fossils found in Wyoming are terrestrial to wetlands (salt water) that indicate a certain type of climate, deposition and predator suites (terrestrial, semi-aquatic and aquatic). Yet these are also the conditions for sudden flash-flood run-offs to happen, meaning that we can get lots of good instantaneous snap-shots of the animal and plant life with just a single, large deposit of animals that all washed together in the bend of a river.

So after going through that part, the History Channel then tries to be 'fair' to all other previous extinction theories about what killed the dinosaurs! Yes the very theories that had problems BEFORE the impact event are now brought up, yet again, to try and say that, you know, they all really died or were nearly gone before the impact... but that isn't what I learned in paleontology class. Here another piece of science comes into play, and its a pretty well known one if you buy life insurance: actuarial tables. Actuarial tables are those tables that track a cohort of people born in a given year and examines their survival rate, and then looks at major factors influencing personal survival. For most age cohorts it is a straight line starting at 100% at zero and going to 0% when the last individuals die off. Ecological suites at the species level can be used in a similar fashion to examine the die-off of species over time. You track only that cohort from the start and examine it over time. Starting near the beginning of the Cretaceous and looking at all known dinosaur species, you get a straight line that is still far above 0% (in the 30% range if memory serves) that suddenly goes to near 0% at the boundary (birds survived). The larger drop-off for all species from the start of the Cretaceous is high, also, and hovers in the 15-20% survival area suffering a major 10-15% drop at the K/T event. There was a major, short-term event that happened that got nearly all the dinosaurs and had a huge global impact on all species.

Note the Deccan Traps were happening, were part of that historical record and showed NO major impact on life on the planet at the species level.

That is not a regular happening to see something like that going on. If you take later cohorts they exhibit the exact, same phenomena. This would be the equivalent of taking everyone in your high school class and everyone else in that same age cohort, on a global scale, and killing them. Plus having the killing be bad enough to endanger enough others in a similar age, but different species (whales, say) go down with you. Plus all the trees that started growing at that time. And a number of others that came up after that, too... so not only those original cohort members (those your age +/- a year globally) but a number of other beings suddenly going 'good-bye' points to something out of the ordinary going on. That would play hell with the life insurance companies, let me tellya.

Next up is the nasty cross-contagion theory! Ok, I now have first-hand, eyewitness accounts of the West Nile virus in the US. I still see, outside my window: Cardinals, Blue Jays, Orioles, Mourning Doves, some finches and sparrows, Red Wing Black Birds... we used to have more finches and sparrows, with lots of Crows, but the others were still there. There appears to be this thing called 'resistance' by some species and lack of it by others to a totally alien virus for the area that usually hits bird populations hard. You know, it sounds as if something else is going on called 'natural selection'. Those that survive breed, those who don't... well... we do have fewer Crows, finches, swallows... but we do have Robins! Plus that wide array mentioned previously. And West Nile is one of the top nasty of all bird bugs around. Birds are dinosaurs, you can look at their skeletons and those as they develop in their eggs and see the major skeletal pieces that are 1:1 similar to their larger family.... guys like the Raptors and T-Rex. Birds got through the K/T most likely due to: small size, diverse eating habits, wide population dispersion to those areas least hard hit, and, yes, insulation in the form of feathers. They were also exposed to the same suite of bugs, diseases, parasites, etc. as their cousins and were far more rapid vectors of those spreading even BEFORE the major land bridges showed up in the Americas.

Perhaps, just perhaps, this idea of 'different species having different resistant traits' is something we would like to explore? You know, epidemiological reasons? Saying that 'close relationship gives close cross-species spread of germs, viruses and parasites' is like saying that Simian Immunodeficiency Virus is tailor made for humans... in fact it needs a lot of modifications via natural selection to do that. There is, apparently, some necessity for these various germs, viruses and parasites to find a proper way to vector from species to species. And then you have the problem of natural resistance, geographic spread (yes dinosaurs migrated to new areas, did they migrate on a continual path from central South America to central North America every year? I doubt it but we do have some evidence of it in birds... those lovely carriers of various germs and such) and population contact. And birds (along with pterosaurs) were perfect at spreading these things before the direct contact itself. Ditto insects tossed around by storms. Rats carried the Black Plague but didn't succumb to it... the 'Typhoid Mary' of their day. And if the migration took generations to tens of generations, mere thousands of years, you will see natural resistance appear and spread in populations as those with them fare better and can have more descendents than those who don't.

When that same geologist who asks the Holocaust equivalent question then proposes a 'time out' to send paleontologist to zoos, he might want to take a trip to Auschwitz himself... and then examine that zoos have unnaturally high concentrations of diverse animal species in formulations that are *not* equivalent to land bridge migrations as animals can move out of the place they are in. Parasites are particularly finicky when it comes to hosts, and there are many worms and other lovely things that will actually take up food in a human's gut, lay eggs and then have all of that be excreted because the natural conditions for them to survive and thrive are absent in their host.

Some great multi-disease spread decimating populations? Or slow spread with lots of generations to adapt? West Nile virus seems to have some limitations as to mosquito type for transmission and different birds have differing resistance to it. The news about an H5N1 virus isn't that it has a 30% mortality rate, but that 70% survive it with some small number being immune to it. That is distribution of resistance in a larger population, and works just as well for dinosaurs as it does for us.

The Deccan Traps flood basalt eruptions in India had major problems as an extinction event before the Impact Theory. First off we have just gone through a period from the end of the Medieval Warm period to the modern era which has seen 'The Little Ice Age' augmented by numerous, small volcanic eruptions. We did, indeed, have a 'year without a summer' in 1816. That was *not* due to the flood basalt eruption in Iceland but to the eruption of Mount Tambora in Indonesia. Typically, while flood basalt eruptions can put out ash and gases of a noxious sort, those are severely limited not by the size of the flood, but by the length of the eruption event laterally (it is a spreading plate eruption, not one building volcanic cones). You can go to Washington State and look at how the rivers have cut through deep layer upon layer of basalt that spread over hundreds of square miles per eruption. Extinction events have not been tied to flood basalt type eruptions, but *have* been tied to places like Mt. Toba and Yellowstone... the fun thing about the Washington flood basaltic depositions is that the hot spot that caused them is still with us under Yellowstone. If the Deccan Traps supporters can find the geochemical evidence for large noxious clouds of lethal proportions blanketing the globe and explain why this was not a pan-die off that poisoned lakes and rivers (thus killing off frogs and fishes and such), I would love to hear it. Proof is in the putting and demonstration, and there are a number of inland lake deposits from the late Cretaceous that should demonstrate this. So far, no luck in finding those fingerprints... nor explaining why that wouldn't kill off in a more shotgun sort of way a different suite of species than what did survive.

Climate change! What a bugaboo that is. The #1 changer to the entire climate at the end of the Cretaceous and that would have severe consequences throughout the Tertiary and Quaternary is mentioned, but only in passing and not in-depth. On the old 'global scale' deal it is *huge*, and yet... it only shows up in reference to another of the 'almost kinda extinction theories if you squint hard enough to close your eyes' deals. It is dead simple, and has had devastating impacts on the biota of the planet after the K/T boundary and points to a long-term shift in climate that was started before it. It is two events, really, but linked together.

First is the speed of the continents. If you think an inch a year is *slow* before the continents decided to get the core-based turbo-boost, it was an inch per century or *more*. The continents started sprinting around the mid Cretaceous which was increasing vulcanism no end, changing land forms and doing all sorts of fun things, like shifting shallow seas off of North America, Europe, Asia, Africa... by going faster the continents ride higher on the mantle than does denser oceanic crust. Slides right over that stuff. General uplift got us the Rocky Mountain Plateau, now over a mile above where it started. Drained out central North America and other regions of the planet. There was lots more of this stuff known as 'dry land' which didn't keep the heat so well as shallow oceans... but even with that the great heat reservoir of the global oceanic current suffered one, huge event due to that volcanic activity caused by the speeded up plates. It is a minor thing, really.


The Atlantic Ocean got cut off from the Pacific via volcanic activity along Central America and uplift there. What had started out as one, huge, oceanic current on a global basis was now broken up into the large Pacific and the growing Atlantic. The shifts in weather patterns when that happened allowed for climates to shift on a scale that could only make a global warming alarmist salivate. Too bad it was done by nature, huh?

To me the fascinating part of the asteroid impact wasn't that it happened near dry land, but that there was dry land there that could be close by to it. A totally sea-based hit would still have been horrific and yielded much the same results, but due to millions of years of uplift and plate movement, there was a Yucatan Peninsula to be hit... not open ocean.

The series of events that followed: shockwaves, tsunamis, firestorm, drought, dust storm, long cold winters with cold summers, has its own set of survival characteristics necessary to it. How you survived depends on the traits you had going in, and as each extinction event going back to the Cambrian has different causes and position of the land masses, you don't know what it will take to survive. Dinosaurs tended towards gigantism given their climate and conditions, but their small cousins we call birds, would come to dominate just *after* the extinction event until another one and massive changes in mammals to fill ecological niches started to happen. We would, absent the impact, have gotten climates with glacial periods... but the modern ecologies that we can examine for those periods points to enough vegetation for large animal survival. The extinction event, however, had a set of survival needs totally different than those normally seen. If you or your young had a way to ride out the event, assure genetic lineages continued, or fit a size and mass range suited to those conditions, you made it.

We would still have dinosaurs around if it weren't for whatever happened at the K/T... we wouldn't be here, however, as the pressure by those animals would keep mammals in the 'burrow for your life' mode of existing. Which was perfect for a suddenly hostile surface environment, that gnawing on roots and going after worms and bugs underground.... plus some scavenging, no doubt, while the bodies of the large dinosaurs hadn't rotted or been roasted to ash. Birds could fly to geographic pockets of survival and watch their big cousins die out, and get a meager existence on whatever showed up in those chilly years after the firestorms ended. They, like mammals, can generate heat to get through winter conditions and feathers are a fantastic insulator. And how many insects, per species, does it take to keep its population going? A few breeding pairs, mostly, but probably way more than that. Frogs and toads would, generally, live off the other eggs and weaker young, plus eat whatever else they could, survive with whatever local conditions allowed and it only takes a few breeding pairs to lay thousands to tens of thousands of fertilized eggs. Eggs that don't mature until it is warm enough for them to do so.

That is not a pleasant pattern to look at, as it is, contrary to how the program presented it, indicative of one major causation with multiple fall-outs. Not some sort of coup de grace by an asteroid. Plus none of the other causes explains the survival modes so well... I am always willing to look at evidence of different ideas. Show the evidence, not speculation... propose the means and then look to see if there is evidence of it and work out what its effects would be. And when there is evidence to the contrary, you must be willing to abandon the theory, no matter how well it fits with what you think, because the evidence points to it being wrong.

But I did notice that most of those doing the propositions for other theories were... well... in the older cohort of geology.

The ones needing to go extinct for science to advance as they have forgotten that evidence over-rides theory.

Even if that has been your life's work.


mark said...

interesting comments. I do think there is still some mysteries involved, though. Like why did only the dinosaurs we call birds make it over the Kt boundary?
there must have been hundreds of small dinosaurs like birds that didn't make it. Why not small pterosaurs too? Some of these are thought to have had something like fur. Also the assumption that all mammals were small, because the dinosaurs so dominated, is just an assumption. There may have been rather large mammals about, we just haven't found the fossils yet. I could easily imagine large islands where there were no large dinosaurs, allowing mammels to grow large. Just like birds and reptiles have done in the modern world. To me. the real extinction mystery, is not the end of the dinosaurs, but the Pleistocene extinctions. I less than an eyeblinck, merely a couple thousand years or less, the megafauna was gone. They are there like a shadow play, we see their shadows move, but can never get a real glimpse of that world. I have seen caves in Arizona where I grew up, that still had groundsloth, and mammoth droppings on the floor. Looking like the animal recently dropped it. You could look at it, and tell what plants had been eaten. Wet it, and it smelled much like horse manure. Yet you can never get your mind around what the animal actually looked like. THATS a real mysery to me. Great commentary.

Joe Katzman said...

Saw something on the Pleistocene. The overkill hypothesis is not robust ( http://scienceblogs.com/laelaps/2008/01/ ).

There's a current theory involving another comet hit, this one a Shoemaker-Levy breakup whose multiple bursts covered most of North America. Evidence is based in part around nano-diamonds. See:


A Jacksonian said...

One of the reasons I go through this is the point made by Gould - that extinction events have a high random variable to them that cannot easily be defined by pure physical features. The part played by physical features is that there is no pre-defined set to determine what will survive an extinction event as each event is different in its nature.

The HC program does a disservice limiting its analysis to just two extinction events (P/T and K/T) due to those having land animals. The Cambrian extinction event, because it is fully aquatic in nature, points to a wholly different mechanism that could knock of phyla of animals - the Cambrian Explosion of diverse life formulation came to a winnowing down to a few basic body plans. You couldn't say what was a 'survivable' body plan without knowledge of the extinction event itself: survival had a high random factor to it.

Similarly the K/T body types have distinctive characteristics that help define what the event did, and anyone trying to piece it together must take those survival features into account...some will survive by random chance others not. Thus the foram species that survived out of the huge diversity of forams must have had features that allowed it to survive when others didn't. Birds surviving but other feathered/furred dinosaurs not surviving must point to something in how birds could get through while pterosaurs and the small remaining dinosaurs couldn't. Mammals, generally, got through by the burrow to survive concept...we have little evidence of dinosaur burrowing animals, so animals of similar ecological niche could be selected for based on secondary survival characteristics... not all pieces play a role and some play a huge role, but we can't determine which is which without specificity of survival traits and population survival. Forams were as devastated as dinosaurs - one body plan making it through while all its variants bit the dust. Ditto the nautilus and all other similar body plans amongst the ammonites. When a swath of body plan is effected and only one gets through, then there is either random chance at play or determinative survival characteristics at play.

In an extinction event each species takes up the dice and rolls them. The dice are weighted, but you don't know how nor what number it is you have to make to survive. If you could run back in time and then restart before any of the major extinction events you would *not* get the same survivors due to the random factors involved. That is a systemic analysis putting in a high random factor with weighting - and it is sobering to realize that until an event happens, you don't know if your qualities, as a species, will allow you, as an individual, to survive. When you examine the survivors you start to understand the weighting involved, which starts to define key characteristics to survive *that* extinction event. The *next* one has an entirely different suite of characteristics and weighting... and you don't know what they are until after the dice have stopped rolling...